It's stunning how little interest mom and pop have in the stock market

"Over the past 10 years, S&P 500 constituents have bought back nearly $4 trillion of stock while investors have added cumulative inflows of less than $100 billion to US equities via mutual funds and exchange traded funds," Citi's Tobias Levkovich said in a note to clients today.

This is not news. But it continues to be a jarring reminder of how stock market mania hasn't permeated Main Street America. Mom and pop just don't care.

"The lack of US retail investor interest in stocks has been stunning and equity market tops usually consist of overly aggressive individual investor interest in the asset class," Levkovich continued. "In this context, it is challenging to suggest that the S&P 500 is due a major correction barring exogenous shocks."